Liquid-dispensing pump and the like



May 11 G. H. WILLIAMS LIQUID DISPENSING PUMP AND THE LIKE Filed July 10, 1925 III May 11, 1926.

lJhil'lE YATES GILBERT H. WILLIAMS, OF DAYTON, OHIO ASSIGNOR TO THE DAYTON MANUFACTURING COMPANY, OF DAYTON, OHIO.

PAT? UFFECE.

PUMP 8s LIQUID-DIS13ENSING PUMP AND THE LIKE.

Application filed July 10, 1925. Serial No. 42,681.

This invention relates to improvements in liquid dispensing pumps.

The main object attained in the invention consists in means for governing the movement of the pump as the pistons approach the finishing point otthe work stroke to prevent over-measurement or" liquid.

It is recognized that any liquid measuring lnunps with a suction lift can, under certain conditions, be made to over-measure by fast running. The following ruling of the United States Bureau of Standards, May, 1922, which is still in effect, is directed to this condition which is common to the prevailing types of liquid dispensing pumps:

Field tolerances allowed by Bureau of Stamlcrds, Weights and Illcasurcs Division.

Factory test tolerances are of the aboveplus or mlnus.

Coastrmey of delic-ery-Smcificction 1V 0. 8,

The amounts delivered by any liquid measuring device shall not vary from the standard by more than the tolerances provided above, irrespective of the speed which the apparatus is operated; provided, however, that when a liquid measuring device is operated faster than normal speed of operation, the tolerance shall be applied in deficiency only; that is the liquid measuring device shall not be deemed to be incorrect by reason of the tolerance in excess being exceeded during such operation.

My invention applied to either single or double cylinder pumps is effective to prevent this error of measurement. The invention is here shown as applied to a double cylinder pump of the type shown in my copending joint application for Patent Serial No. 725,- 964:, filed July 14, 1924, the application of the invention as made in the accompanying drawings being for the purposes of illustration.

In the drawings:

Fig. 1 is an elevation of the pump in" longitudinal section;

Fig. 2 is a detail cross-sectional view of the pump cylinder and piston illustrating the application of my invention thereto.

The invention, as here shown, comprises a pump cylinder 1, a piston 2 operable inthe cylinder, suitable piston operating means, as the piston rod 3, rack 4 and actuating gearing 5, the'details of construction embodying the invention being confined to the cylinder and piston, as best shown in Fig. 2.

As here shown, the cylinder head 6 is provided with an inner annular flange 7 serving to form a chamber liquid trap 8, and the piston is provided with an annular flange or sleeve 9 operable as apiston in flange 7 as piston 2 approaches the limit of movement on the work stroke, thus causing the liquid in chamber 8 to be under pressure and to act as a cushioning element on the piston, the liquid being discharged under pressure through a port 10 into free space surrounding chamber 8. Thus it will be seen that the force or momentum of the piston and of the upward movement of the'liquid itself will be broken by the gradual resistance of the liquid in chamber 8 on the piston, and that the discharge of liquid in excess of the measurement which could otherwise result upon rapid operation of the pump will be prevented.

While the means described for preventing over measurement of the pump, as applied to the head of the cylinder, will be effective, it is desirable to provide the cushioning element at both ends of the cylinder as a further aid to prevent abrupt ending of the stroke of the pistons in both directions of operation.

To this end, the lower ends of the cylinders are provided with a liquid trap 12 having a chamber 13 which will be normally filled with liquid on the down stroke of the piston. The opening of the trap is cylindrical and is adapted to receive in close fitting rela tion, as the piston approaches the limit of the downward movement, a downwardly extended cylindrical portion 14 of the piston in the same manner as part 7 receives part 9 in the up stroke at the piston, and with a similar cushioning action of the liquid on the piston, a port 15 acting to permit of gradual escape of the liquid from chamber 13 to give the desired retarding effect to the movement of the piston. On the rise of the piston the liquid passes freely through a series of ports 16 to the cylinders.

Having described my invention, I claim:

1. A pump including in combination with a cylinder and a piston operable in the cylinder, a chamber formed in the head of the cylinder adapted to be filled with liquid on the work stroke of the piston, and means associated with the piston and coacting with said chamber to cause a cushioning action of the liquid therein on the piston as the same approaches completion of the stroke.

2. A pump including in combination with .a cylinder and a piston operable in the cylinder, a chamber formed in the head of the cylinder adapted to be filled with liquid on the work stroke of the piston and having a port for the discharge of liquid from the chamber, and means operable with the piston and coacting with said chamber to cause a gradual cushioning action of the liquid therein on the piston as the same approaches completion of the stroke.

3. A pump including in combination with a cylinder and a piston operable in the cylinder, means associated with the head of cylinder acting to confine a quantity of liquid under pressure of the piston on the work stroke thereof, and means permitting gradual escape of the confined liquid whereby to effect a gradual resistance of the movement of the piston as the same approaches completion of the stroke.

4. A pump including in combination with a cylinder and a piston operable in the cylinder, a chamber formed in the head of the cylinder adapted to be filled with liquid on the work stroke of the piston, and a member operable as a unit with the piston and adapted to be moved into pressure relation with the liquid in said chamber whereby to effect gradual resistance to the movement of the piston as the same approaches completion of the stroke.

5. A pump including in combination with a cylinder and a piston operable in the cylinder, a chamber formed in the head of the cylinder adapted to be filled with liquid on the work stroke of the piston, and a member supported on the piston and adapted to react as a piston with said chamber to discharge the liquid therefrom whereby to effect gradual resistance to the movement of the piston as the same approaches completion of the stroke.

6. A pump including in combination with a piston operable in a cylinder, a plurality of chambers formed in the cylinder, one at each end thereof, each adapted to be filled with liquid, and means carried by the piston and coactive with said chambers to effect gradual resistance to the movement of the piston as the same approaches completion of its stroke in opposite directions.

7. A pump including in combination with a piston operable in a cylinder, a chamber formed in the cylinder, near one end of the movement of the piston, and adapted to be filled with liquid, and means carried by the piston and coactive with said chamber as the piston approaches the chamber to cause the liquid to gradually retard the movement of the piston to effect gradual resistance to the movement of the piston toward said chamber.

In testimony whereof, I afiix my signature.

GILBERT H. lVILLIAMS. 

